Cocoa powder rich in polyphenols, process for producing the same and modified cocoa containing the same

ABSTRACT

The invention provides a treating process of cacao beans, and more particularly cacao powder rich in polyphenols, a process for the preparation thereof and a prepared cacao composed of the cacao powder. According to the invention, the polyphenol contained in the cacao beans is allowed to remain as much as possible, by setting initial water content in the roasting treatment to 3-10% by weight. Although polyphenols have various favorable biological functions of anti-oxidating action, anti-dental cariesing action, action for preventing arteriosclerosis and so on, but those are unfavorable from the view point of taste because of astringency and bitterness. In a conventional process for preparing cacao powder, therefore, an operation for removing polyphenols has been carried out, but in the invention, the astringency and bitterness are inhibited by setting water content of the cacao nib to 3-10% by weight in the alkali treatment prior to the roasting treatment. Therefore, the invention provides a high functional cacao powder with good taste.

TECHNICAL FIELD

The present invention relates to a process for treating cacao beans andmore particularly, a cacao powder rich in polyphenols, process for thepreparation thereof and prepared cacao comprising the same.

BACKGROUND ART

A conventional cacao powder has been prepared through steps of crushingwashed raw cacao beans to remove a shell and embryo and obtain a cacaonib, treating with an alkali the cacao nib, roasting the cacao nib,grinding the roasted cacao nib, expressing oil, and pulverizing the oilexpressed substance.

In general, the alkali and roasting treatments are started with suchinitial conditions that an amount of water is 10-25% by weight inclusiveof moisture in the cacao nib and pH is 6.8-8.0.

The prepared cacao is prepared by adding sugar, powdered milk and thelike to the cacao powder prepared as above to adjust its taste, and ifnecessary, agglomerating the resulting mixed powder. A cacao beverageprepared by dissolving the prepared cacao with hot water has been widelyand habitually drunk.

While, the polyphenols are watched substances with great interest, sincesuch reports have been made through recent studies that the compoundshave various and biologically favorable functions inclusive ofanti-oxidating action, anti-dental caries action, action for preventingarteriosclerosis, inhibiting action of carcinogenesis, anti-stressingaction, anti-bacillus and virus actions, anti-allergy action and others.

However, a cacao polyphenol (may be abbreviated hereinafter as “CMP”)which is one of polyphenols and contained in the cacao beans showsastringency and bitterness, and thus a cacao powder containing CMP inhigher amount can not be said as preferable one from view point oftaste. In the conventional process for preparing the cacao powder,therefore, the cacao nib is treated with the alkali to increasesolubility and reduce the astringency and bitterness and in other words,the process reduces the amount of CMP originally presenting in the cacaobeans. Therefore, there is no measure other than increasing the intakingamount of the cacao beverage or using a prepared cacao which containsthe cacao powder in excess amount, is not well-balanced with the sugarand milk and is not preferable from view point of taste, in order tointake the biologically favorable CMP as much as possible by using anadjusted cacao composed the conventional cacao powder.

DISCLOSURE OF INVENTION

Basic objects of the invention, therefore, to provide a process forpreparing a cacao powder under treating conditions which do not reducean amount of CMP presenting in cacao beans, as possible, the cacaopowder rich in CMP, to be obtained by the process, and a prepared cacaocomprising the cacao powder.

Final object of the invention lies in providing a good cacao powderwhich is not spoiled in taste, in spite of that its CMP content is keptin higher level, to make easy intake of CMP which is excellent infunctions.

The inventors have energetically studied and investigated for dissolvingsaid problems and attaining said objects. As a result, they haveobtained such findings to establish the invention that preparation ofthe cacao powder rich in CMP (may be abbreviated hereinafter as “HPC”)is possible by adjusting roasting conditions of a cacao nib, and thatthe astringency and bitterness inherent to CMP can be sharply inhibitedby adjusting treating conditions with an alkali, prior to the roastingtreatment, in spite of that the cacao powder has relatively high CMPcontent and although an amount of CMP somewhat reduces than thatcontained in the cacao beans.

Namely, the invention relates to a process for preparing a cacao powderrich in polyphenols, which is characterized by subjecting a cacao nib toan alkali treatment under water content condition of 3-10% by weight orthe cacao nib to a roasting treatment by setting initial water contentof 3-10% by weight, without carrying out the alkali treatment, and thencarrying out steps of grinding, oil expression and pulverization, inorder; the cacao powder obtained by the process; and a prepared cacaocomposed of the cacao powder.

The basic matter of the process according to the invention lies in thatthe amount of CMP presenting in the cacao beans does not reduce, aspossible, through steps for preparing the cacao powder and thus, it ispreferable to use cacao beans in kind and place of production, whichcontain CMP in higher level, as much as possible, in order to obtain acacao powder rich in CMP. For instance, the cacao beans produced inGhana, which have been widely selected for preparing the cacao powdercontain CMP of about 3.3% by weight in raw beans, and while the cacaobeans produced in Ecuador show higher CMP content of 3.6-6.3% by weightand thus, it is advantageous to use the cacao beans produced in Ecuador,since the amount of CMP is higher than those produced in Ghana. Thecacao beans produced in Venezuela can be exemplified as those containingCMP in higher amount, excepting those produced in Ecuador.

In case of carrying out the process according to the invention, taste offinally obtained cacao powder becomes good, if an alkali is added tomake final pH to 5.0-7.5 and more preferably to 6.6-7.0, in the alkalitreatment. When potassium carbonate, sodium carbonate or the like isused as the alkali, it is preferable to add the same in an amount notexceeding 2.0% by weight to the cacao nib.

It is preferable to set water content in the cacao nib in a reactionvessel for subjecting the cacao nib to the alkali treatment in lowerlevel, as possible, so that CMP presenting in the cacao beans remains inan amount as much as possible. Since moisture contained in the cacao nibper se is 3-7% by weight, in usual cases and thus it is necessary tocarry out the treatment under the water content condition of 3-10% byweight, by setting possible adding water of an amount not exceeding 7%by weight.

Further, it is preferable to carry out the alkali treatment undercontrols of temperature in a range of 50-100° C. and stirring timeperiod in a range of 5-30 minutes to finish the reaction under lowertemperature condition and shorter period of time, as possible, so as toremain CMP as much as possible.

In the roasting step for carrying out the process according to theinvention, it is preferable to set shorter roasting period of time, inorder to remain CMP presenting in the cacao beans in maximum level, butit necessary to consider various conditions on an amount of addingwater, temperature, roasting period of time and others, in response tokind of the cacao beans for taking out inherent flavor and taste due tothe kind of cacao beans. In a usual case, such conditions for theroasting treatment are preferable as standards that initial watercontent is 3-10% by weight, final temperature of the cacao nib is120-125 C., and roasting period of time is about 30-50 minutes. Forinstance, the cacao nib with nice taste can be obtained by if necessary,adding water to make water content of the cacao nib at roast startingtime as 10% by weight and then roasting the same for 40 minutes, so asto reach final temperature of the roasted cacao nib to 123 C. (finalmoisture content of the roasted cacao nib: about 2% by weight), when thecacao beans produced in Ecuador are selected. In case of the cacao beansproduced in Ecuador, bright flavor inherent to the beans becomes strong,but grassy-smelling generates, when the final temperature of cacao nibis lower than 123 C., and the flavor becomes poor and taste becomesheavy feeling, when the roasting is carried out until the finaltemperature of cacao nib exceeds 123 C.

It is preferable that moisture content of the roasted cacao nib is 1-5%by weight and in such a range of moisture content, almost no lowering ofCMP content occurs in subsequent grinding and oil expressing steps.

The subsequent step of oil expression from the roasted cacao nib can becarried out in a conventional manner. In the conventional cacao powder,there are two types containing oil as final content of 12-14% by weightand 22-24% by weight, but it is preferable to carry out the oilexpression, so that the final oil content becomes 12-14% by weight, toincrease CMP content therein. When the process according to theinvention is carried out with use of the cacao beans produced inEcuador, HPC containing CMP of 7-11% by weight can be obtained bycarrying out the oil expression, so as to make the final oil extent to12% by weight. In this case, HPCs containing CMP of 7-9% by weight haveproper astringency and bitterness to show nice taste.

When the oil expression is carried out, so as to make final oil extentto 22% by weight, HPCs containing CMP of 6-10% by weight can beobtained.

The prepared cacao can be obtained by composing a saccharoid, powderedmilk and edible additive(s) in the HPC and mixing the same oragglomerating mixture in the form of powder in a conventional manner.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 shows a relation between moisture content in cacao nib which hasbeen alkali treated or just prior to roasting treatment and without thealkali treatment and content of cacao polyphenol (CMP) in finallyobtained cacao powder.

BEST MODES FOR CARRYING OUT THE INVENTION

Now, the invention shall be explained in more detail and concretely withreference to Examples, Comparative Examples and Test Examples.

A measurement of cacao polyphenol in the cocoa powder obtained by theExamples and Comparative Examples had been made by following method.Namely, the resulting cacao powder was treated by hexane for defattingand treated by water-containing methanol for extracting CMP in the cacaopowder, and then an amount of CMP was measured by the prussian bluemethod. As the water-containing methanol, 50% aqueous methanol solutionwas used, and the prussian blue method was carried out in accordancewith that described in “Methods in Enzymology”, Vol. 234, pages 432-433(edited by Packer), in which commercially available epicatechin wasselected as standard compound.

EXAMPLE 1

To a cacao nib obtained in a conventional manner from cacao beansproduced in Ecuador, a solution of 0.9% by weight of potassium carbonatein 1.35% by weight of water was added and pH thereof was adjusted to6.8. The resulting solution was poured into a reaction vessel withjacket temperature at 100 C., and stirring was started, when temperatureof the solution reached 50 C. and continued for 15 minutes for alkalitreating the cacao nib. Temperature of the solution at the time, whenthe reaction was just finished, was 80 C. and moisture content of thealkali treated cacao nib was 6.1% by weight. To the alkali treated cacaonib, water of 3.8% by weight was added and roasting thereof wasinitiated by an indirect heating type roaster and the roasting treatmentwas carried out until the final temperature of the cacao nib reaches 123C. for 40 minutes. After ground the roasted cacao nib, oil expressionwas carried out, so as to make oil content to 12% by weight, and thenpulverized to prepare HPC.

EXAMPLE 2

HPC was prepared by the process similar to that described in Example 1,excepting that the alkali treatment was omitted and roasting treatmentwas initiated under initial conditions of moisture content of 5.0% byweight and pH of 5.7.

EXAMPLE 3

To 16% by weight of HPC obtained by Example 1, 40% by weight of sugar,23% by weight of lactose, 15% by weight of total powdered milk, 5% byweight of defatted milk powder and 1% by weight of other ediblematerial(s) were composed to prepare a powdery prepared cacao or thepowdery prepared cacao was subjected to wet agglomeration to prepareprepared cacao granules comprising HPC.

The prepared cacao shows nice taste and excellent in solubility, andcontains CMP in twice amount, in comparison with a prepared cacao havinga composition same with the above, excepting of using general orconventional cacao powder (CMP content: 3.9% by weight) and inaccordance with a process similar to that described in ComparativeExample 1 given later, excepting that cacao nib derived from cacao beansproduced in Ghana was used and oil was expressed until oil contentreaches 22% by weight.

Comparative Example 1

A process similar to that described in Example 1 was carried out toprepare cacao powder, excepting that to cacao nib derived from cacaobeans produced in Ecuador, a solution of 1.8% by weight of potassiumcarbonate in 12.7% by weight of water was added and pH thereof was 6.8,the resulting solution was poured into a reaction vessel with jackettemperature of 120° C., an alkali treatment was carried out at 120° C.under steam pressure and stirring for 20 minutes, and then roasting wascarried out to the alkali treated cacao nib with water content of 23.0%by weight.

Comparative Example 2

A process similar to that described in Example 1, excepting that tocacao nib derived from cacao beans produced in Ecuador, water of 10.0%by weight was added and pH thereof was 6.0, a treatment of heating at120° C. under steam pressure and stirring for 20 minutes in a reactionvessel with jacket temperature of 120° C. was carried out in lieu of thealkali treatment, and then roasting was carried out to the resultingcacao nib with water content of 23.0% by weight.

Test Example 1

CMP content in the cacao powder obtained by Examples 1 and 2 as well asComparative Examples 1 and 2 was measured, respectively and taste ofeach cacao powder was evaluated. Results are shown in following Table 1.

TABLE 1 CMP content Taste evaluation Example 1 7.8 (% by weight) good :weak astringency and bitterness, and light aroma. Example 2 8.8 approve: somewhat strong astringency and bitterness, and there is favorablearoma. Comparative 3.0 good : no astringency and Example 1 bitterness,and nice favorable aroma. Comparative 3.7 approve : noticeable Example 2astringency and bitterness, and there is favorable aroma.

Test Example 2

Various cacao powders were prepared according to the process similar tothat described in Example 1, excepting that water content of the alkalitreated cacao nib are different, and the process similar to Example 2,excepting that water content of the non-alkali treated cacao nib justbefore the roasting treatment are different, to compare CMP content ineach cacao powder and the initial water content of the cacao nib in theroasting treatment.

Results are shown in FIG. 1. It became clear that the repression ofwater content in the cacao nib during its alkali treatment, as lower aspossible, is preferable, in order to increase remaining amount of CMP inthe cacao powder, and CMP content in the cacao powder can be made to 7%by weight or more, when water content in the cacao nib at the beginningof the roasting treatment is repressed to 10% by weight or less.

Industrial Applicability

Cacao beans contains polyphenols which have been recently reported asthe substances having biologically favorable functions inclusive ofanti-oxidating action, anti-dental caries action, action for preventingarteriosclerosis and others. However, the polyphenols show astringencyand bitterness and thus cannot be said as a preferable ingredient fromview point of the taste. Hitherto, therefore, cacao beans containing thepolyphenols in lower amount have been used for preparing cacao powderand the conventional process for preparing the cacao powder contains astep for lowering content of the polyphenols. On the contrary thereto,the invention provides cacao powder remaining polyphenols in largeamount as much as possible and shows excellent taste. Therefore, thecacao powder according to the invention is excellent in its functions.

What is claimed is:
 1. A process for preparing a cacao powder rich inpolyphenols, comprising the steps of: roasting a cacao nib having awater content of 3% to 10% by weight; grinding the roasted cacao nib;expressing the oil from the ground cacao nib; and pulverizing the oilexpressed substance, thereby to produce a cacao powder having a cacaopolyphenol content of 7% to 9% by weight.
 2. A process as claimed inclaim 1, characterized in that said oil expression is carried out, so asto make final oil content of the cacao powder to 12-14% by weight.
 3. Aprocess as claimed in claim 2, characterized in that the cacao nib issubjected to an alkali treatment under condition of water content of3-10% by weight, prior to the roasting treatment.
 4. A process asclaimed in claim 3, characterized in that said alkali treatment iscarried out by adding an alkali to the cacao nib in an amount notexceeding 2.0% by weight and adjusting final pH to 5.0-7.5.
 5. A processas claimed in claim 1, characterized in that the cacao nib is subjectedto an alkali treatment under condition of water content of 3-10% byweight, prior to the roasting treatment.
 6. A process as claimed inclaim 5, characterized in that said alkali treatment is carried out byadding an alkali to the cacao nib in an amount not exceeding 2.0% byweight and adjusting final pH to 5.0-7.5.
 7. A process as claimed in anyone of claim 1, 2, 5, or 6, characterized in that said cacao nib is thatderiving from cacao beans produced in at least one of Ecuador andVenezuela.
 8. A cacao powder rich in polyphenols, which is obtained bythe process described in any one of claim 1,2,5 or
 6. 9. A cacao powderrich in polyphenols as claimed in claim 8, characterized in that cacaopolyphenol content is 7-9% by weight.
 10. A prepared cacao characterizedin that cacao powder rich in polyphenols and described in claim 9 iscomposed therein.
 11. A prepared cacao characterized in that cacaopowder rich in polyphenols and described in claim 8 is composed therein.12. A cacao powder comprising a cacao polyphenol content of 7% to 9% byweight produced by performing the steps of: roasting a cacao nib havinga water content of 3% to 10% by weight; grinding the roasted cacao nib;expressing the oil from the ground cacao nib; and pulverizing theremaining cacao nib.